Rev. 13 November 1, 2016
Page | 78c. Disconnect switches used with motor-driven appliances, and motors and controllers shall be installed within
sight of controller position.
d. Where installed on the load side of a VFD, the disconnect switch shall be labeled stating the location of the
VFD, or it shall contain a normally open interlock which is connected to the VFD. This interlock wiring must
be in a separate raceway. The interlock engages before the phase conductors are disconnected and the VFD
knows to shut down before the motor is disconnected from it.
e. Transformers shall be installed on vibration mounts and connected with liquid-tight flexible conduit (24”
minimum length).
f. Provide grounding c onnections to assure permanent and effective g round for transfor mers.- Applications:
a. Perfor m voltage dr op calculations on all feede rs. Increase conductor sizes where necessary.
b. Perfor m short circuit calculations on the ne w or modified portions of the electrical distribution system.
c. Circuit breakers in new panelboards and switchboards shall not take up more than
75% of the available bus space (25% shall be for future use).
d. Utilize surface mounted pane lboards in dedicated electri cal rooms. Where flush branch circuit pane ls
are used in finishe d spaces, stub five ¾” and one 1 ¼” empty conduit out of pane l to above an accessible
ceiling a rea.
e. Use K-rated transformers whe re they serve hi gh harmonic loads such as computer rooms.
f. Utilize expansion fitti ngs on bus du cts, cond ui ts, a nd cabl e trays where they cross building expansion joints.
26 24 00 Switchboards and Panelboards26 24 13 Switchboards- Switchboards shall be factory assembled, dead-front, metal enclosed with copper bussing and copper ground bar.
Provisions for additional circuit breakers shall be such that field addition of connectors or mounting hardware will
not be required to add circuit breakers to the switchboard. - Utilize Square D Power Logic to match the existing monitoring system.
- Switchboards shall be listed for service entrance where applicable.
- The basis of design shall be Square D I-Line Series.
26 24 16 Panelboards- Distribution Panelboards
a. Distribution panelboards shall be factory assembled, dead-front, metal enclosed with copper bussing and
copper ground bar. Provisions for additional circuit breakers shall be such that field addition to connectors or
mounting hardware will not be required to add circuit breakers to the panelboards. Fronts shall include
hinged doors and have flush, stainless steel, cylinder tumbler-type locks with catches and spring- loaded door
pulls.
b. The basis of design shall be Square D I-Line Series. - Isolation Panels
a. In patient care areas determined by the Owner to be “wet locations” during times when patients are present,
Isolated Power Panels shall be provided. Inside the room a line isolation monitor (LIM) shall be provided.
These panels supply uninterrupted power in the event of a line-to-ground fault, while eliminating the danger
of electrical shock.